Duplicating process employing magnetic developer material



United States Patent [72] Inventors Morton Silverberg Rochester, New York;

Matthew P. Tubinis, Rochester, New York [21] Appl. No. 589,097 [22] Filed Oct. 24, 1966 [45] Patented Sept.l,l970 [73] Assignee Xerox Corporation Rochester, New York a corporation of New York [54] DUPLICATING PROCESS EMPLOYING MAGNETIC DEVELOPER MATERIAL 7 Claims, 12 Drawing Figs.

[52] US. Cl 101/426, 117/17.5, 1 18/637, 346/74 [51] Int. Cl. 603g 19/00 [50] Field ofSearch 117/17.5;

346/74MP; IOI/ESD; 118/637; 101/426 [56] References Cited UNITED STATES PATENTS 2,040,075 5/1936 Brower 117/36.1X 2,216,594 10/1940 Marchev 117/36.1X 2,841,461 7/1958 Gleason 117/17.5X 2,857,290 10/1958 Bolton 117/17.5

2,884,348 4/1959 Kulesza 117/17.5X 2,943,908 7/1960 Hanna 346/74 2,990,278 6/1961 Carlson 117/1 7.5X 3,120,806 2/1964 Supernowicz 117/17.5X 3,161,544 12/1964 Berry 1l7/17.5X 3,239,465 3/1966 Rheinfrank l17/17.5X

' Primary ExaminerWilliam D. Martin Assistant Examiner- Edward .1. Cabic Attorney-James J. Rolobati, Norman E. Schrader and Ronald Zibelli AEiSTRACT: A duplicating process wherein magnetic images of Copy to be reproduced are created and used to attract magnetieally attractable powder to form subsequent reproductioris'of the original copy. The magnetic images are deposited and fused to a sheet to form a master. The magnetic field extending from the master can be used to either attract magnetic toner directly to the fused image on the master with subimage. These toner images are then fused to the copy sheet. 3 Mirror images can be avoided by transferring the toner images to intermediate surfaces or by producing the master in a reverse reading form.

4 Patented Sept. 1, 1910 3,526,131

Sheet of 3 POWER 7 SOURCE Z5 INVENTOR. MORTON SlLVERBERG MATTHEW P. UBINIS ATTO Patented Sept. l, 1976 3,526,191

Sheet 2 of 3 INVENTOR. MORTON SILVERBERG MATTHEW P. TUBINIS Patented Sept. 1, 1976 Sheet INVENTOR. MORTON SILVERBERG DUPLICATING PROCESS EMPLOYING MAGNETIC DEVELOPER MATERIAL This invention relates to process and apparatus for recording information onto a copy sheet. More specifically, the invention relates to a novel copy duplicating system for producing high quality, high volume copy at relatively low unit cost.

Various systems are well known for high volume duplicating of copies including mimeograph, spirit duplicating, lithography, and the like. At the same time there are known reproduction systems generally regarded as more suitable for lower volume rates such as xerography and photography which offer the distinct advantage of an optical input in reproducing copy of an original.

Now in accordance with the instant invention there is provided a novel copy duplicating system suitable for high volume copy at low cost per copy and produced from a magnetic image master which can be formed from an optical or electrical input such as xerography, or can otherwise be formed by ink transfer as from a specially prepared typewritter ribbon.

It is therefore an object of the invention to provide novel method and apparatus for copy duplicating. I

It is a further object of the invention to provide a novel copy duplicating system suitable for high volume rates of duplication at low relative cost per copy.

It is a still further object of the invention to effect copy duplicating with a master that can be easily and simply formed with or without an optical input on a combination thereof.

These and other objects of the invention are obtained by means of forming a master copy of the image to be reproduced with magnetic ink capable of repeated subsequent development with magnetic ink particles which are separately transferable in image configuration to a copy support.

For a better understanding of the invention disclosed as well as other objects and features thereof, reference is had to the following detailed description of the invention to be read in conjunction with the accompanying drawings wherein:

FIG. I (a-e) illustrates a series of sequential steps in accordance with one embodiment ofthe invention;

FIG. 2 is a schematic apparatus embodiment for automatically performing the process in accordance with FIG. 1; and

FIG. 3 (aj) illustrates a series of sequential steps in accordance with a second embodiment of the invention.

In accordance with the first embodiment hereof there is at least partially employed the process of xerography as for example disclosed in Carlson U.S. Pat. No. 2,297,691 issued October 6,1942, or may include variations thereof for placing a developable image charge pattern on a support as disclosed, for example, in U.S. Pat. Nos. 2,825,814; 2,919,967; and 3,015,304. Likewise a latent magnetic image could be formed and utilized as disclosed in U.S. Pat. No. 2,857,290. As first taught by Carlson a xerographic plate comprising a layer of photoconductive insulating material on a conductive backing is given a uniform electric charge over its surface and is then exposed to the subject matter to be reproduced, usually by conventional projection techniques. This exposure discharges Whatever technique is employed initially for forming the latent image pattern, it is subsequently developed by means of a developer material 15 contained in a hopper 16 having an outlet 17 from which the developer cascades over the charge pattern to effect development and then into a receiving bin 18. The developer marking material, as will be understood, is critical to the invention to the extent that the developed image must per se comprise a permanently magnetized material or material which can be readily magnetized at some step in the process subsequent to development. Accordingly, the developer marking material can comprise various known materials usable in the xerographic art having magnetic or magnetizable components with or without an electroscopic coating, and capable of being attracted to an image pattern of electrostatic charge or magnetic fields. For these purposes, therefore, the developer can include suitable materials such as those described in U.S. Pat. Nos. 2,846,333; 2,970,299; 3,093,039; 3,106,479; 3,155,53l; as well as such other developers known to those skilled in the art.

After development the developed image designated 20, is transferred to a secondary transfer sheet 21 to effect an image reversal from that developed and comprises the master pattern as will be understood.

Where an image reversal is unnecessary, depending on the optical input or other approach to forming the developable This is particularly so where support 11 comprises a consumable product such as well known forms of zinc oxide photoconductive papers.

In the embodiment shown, transfer is effected as shown in FIG. 10 by means of a corona generator 22 that is driven via axial screw 23 to apply an electrostatic transfer charge onto the rear surface of the transfer sheet. After transfer the transferred image is fused to the master pattern by means well known in the art as by application of heat from a fuser 27 including a radiant coil 25 energized from a power source 26.

The master thus formed can be employed for effecting subsequent copy duplication and for this purpose is mounted upon a continuously driven cylindrical drum 29. A magnetic member 24, which can comprise a permanent magnet or an electrically or electronically controlled magnetic field member supplies a magnetic field to the image to effect a magnetization thereof. As the drum is rotated, a copy sheet is fed via a feed mechanism 31 from a paper supply contained in a tray 30. Thetop sheet of the stack is continually fed onto a set master sheet, the top side thereofis brushed by a development .brush assembly 36 receiving developer particles 37 from a hopper 38. The developer particles may be similar to that emthe plate area in accordance with the radiation intensity that reaches them, and thereby creates an electrostatic latent image on or in the photoconductive layer. Development of the.

latent image is effected with an electrostatically charged, finely divided material such as an electroscopic powder that is brought into surface contact with the photoconductive layer and is held thereon electrostatically in a pattern corresponding to the electrostatic latent image. Hereafter, the developed xerographic image may be affixed directly to the surface on which it is developed or as usually performed, is transferred to a secondary support on which it is affixed by any suitable means.

In accordance with the embodiment of FIGS. la-Ie there is first formed, as shown in FIG. 1a, a charge pattern of copy to be reproduced represented by the plus signs 10 on the surface of a support 11. Support 11 may comprise a photoconductive layer 12 on a conductive substrate 13 that has been xerographically processed as described above.

ployed initially in the preceding steps of forming the master and generally comprises a magnetic powder or magnetically attractable powder such as iron particles in a plastic coating. The particles retained on the brush surface are attracted to the top side of the copy sheet in image configuration as a result of the magnetic field emanating from the polarized image on the master below. This then forms a direct duplication of a master pattern on the copy sheet 33 which then passes below a fuser 27 as above before depositing into a collection bin 40. Thus, with each rotation of drum 29 a copy sheet 33 is fed from the stack in tray 30 into development position in register with the master pattern 21. This therefore enables a high volume high speed duplication of the master pattern. The polarized characteristics of the image enables substantial quantity duplication since wear on the master is less significant than with other known duplicating processes.

Referring now to FIG. 2 there is schematically shown an apparatus embodiment for continuous automatic operation of the aforesaid steps described in connection with FIG. 1. The components for forming a charge pattern of a document 44 to be duplicated is similar to that disclosed in U.S. Pat. No.

3,076,392. The document original is placed on a support tray 46 from which it is fed onto a conveyor 47 whereat it is reflected into an optical system 48 for projection onto the precharged surface ofa continuously rotating drum 45. As the drum surface advances the electrostatic latent image of the document formed on exposure passes through a developing station 49 whereat developer material as above is caused to cascade over the drum surface to effect image development. After development, the developed image is transferred to a continuous web or master sheet 21 supplied from a reel 51 to pass in contact with the drum surface in the vicinity of corona generator 22. As before, the image is rendered permanent by fuser 27 and magnetized by magnetic member 24. Thereafter, the web advances past a plurality of separate duplicating stations 52a to 52n until passing onto a takeup roll 53 being driven by a motor 54.

Each of the duplicating stations designated 52a to 52n are adapted to reproduce each of the master patterns contained on web 21. Each therefore includes a supply of continuous copy web material 56 advancing from a supply reel 57 over a pair of guide rolls 58 and 59 between which it passes in register with the advancing master pattern 21. As in FIG. 1e above the top surface of web 56 while within the image field in contact against the master pattern, receives a quantity of developer 37 from a brush unit 36 to effect an image duplication thereon. The web then passes below fuser 39 onto the takeup roll 60.

In FIG. 3 there is shown the second process embodiment in accordance with the invention hereof in which an original document 70 is prepared on an ordinary typewriter 71 using a specially prepared ribbon 72. The ribbon is prepared having an ink containing particles impregnated therein which can be magnetized. Various forms are known in the art including those used conventionally in magnetic ink character recognition characters and suitable inks disclosed in British Pat. 882,138. This document comprises a master from which subsequent copies could be made in the manner of FIG. 2.

The original document 70 thus formed is then placed on support 73 as shown in FIG. 3b The master image on document 70 is then magnetized by passing magnet 74 across the surface and the image is dusted with a developer similar to that described above. The developer adheres restrictively to the document surface in the image character or magnetized areas. ln order to obtain a reverse reading or mirror image for subsequent duplicating the layer of developer or powder is transferred from the document sheet 70 to a developer receptive secondary support 75 via a pair of driven pressure rolls 76 and 77 shown in FIG. 3c. The transfer can be effected by either using a secondary support 75 which has an adhesive surface or by attracting the particles to the surface by magnetic attraction. The image may then be fused to the surface of sheet 75 and magnetized in the same manner as described above. Thereafter the sheet 75 is a master sheet which may be wrapped onto the periphery ofa drum 29 for continuous rotation therewith. The drum advances the image pattern into contact with a developing brush 36 which presents developer particles 37 to the image and which attract and loosely adhere to the image areas by magnetic attraction. Along with further advance a copy sheet 33 is fed from the top of a paper stack contained in tray to arrive in register with the image pattern on the drum. An electrostatic transfer member 79 effects transfer of the loosely held particles from the image pattern on the master sheet 75 to the copy sheet 33 Here again the image may be transferred by using an adhesive surface on the copy sheet. The copy sheet then continues beneath fuser 27 before dropping into receiving tray 40.

As can be appreciated. and as has been already mentioned above as a variation of this latter embodiment. the original document can per se comprise a master pattern for mounting onto the drum 29. That is, where optically correct or by subsequently developing without transfer on the top side of copy sheet 33 in the manner shown in FIG. 10, the transfer step shown in FIG. 30 can be eliminated.

As a still further variation of this latter embodiment in order to obtain an optic reversal of the image characters on the document they are formed on the backside thereof by a backfacing carbon-like sheet or the like. Spirit duplicating master sets are conventionally prepackaged in this manner such that an ordinary typewriter ribbon can be used in the preliminary image forming step. For these purposes the carbon-like sheet would include an incorporated magnetic ink as above. The document is then processed as in FIGS 3b, d, and e omitting the transfer step illustrated in FIG. 30.

By the above description there is disclosed a novel duplicating process and apparatus that is both simple and expedient yielding high volume duplicating of image reproductions to relatively low unit costs.

Since many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the drawings shall be interpreted as illustrative and not in a limiting sense.

We claim:

1. An image duplicating process comprising the steps of:

forming a pattern of images with a magnetizable marking material on a first support means; magnetizing said material comprising said images; forming subsequent images of magnetic developer powder on a second support means by using the magnetized images to attract said magnetic developer powder into image configuration of the original formed image; and

permanently fixing said subsequent images on said second support means.

2. The process according to claim 1 in which the magnetically attractable marking powder is attracted directly to said original image and is subsequently transferred to a support sheet and permanently affixed thereto.

3. The process according to claim 1 in which the step of forming a pattern is accomplished by typing image characters with a ribbon impregnated with magnetic ink.

4. The process according to claim 1 in which the original pattern of images is formed by typing on a first support means which is backed by a carbon sheet consisting ofa material hav ing magnetic properties thereby forming a magnetic reverse image on the first support means and said magnetically attractable marking powder is attracted to the carbon image on the first support means and subsequently transferred to said second support means.

5. An image duplicating process comprising the steps of:

forming a pattern of images with a magnetizable marking material on a first support means;

magnetizing said material comprising said images;

superimposing a second support means over the original formed images of magnetized marking material causing the magnetic field of said images to pass through said second support means and attract magnetically attractable marking powder on to the surface of said second support means in image configuration, and fixing said marking powder to the surface of said second support means before said second support means is separated from the original image.

6. An image duplicating process comprising the steps of:

forming xerographic images on a first support sheet with magnetizable powder;

fusing said formed images to the surface of said first support sheet; subjecting said fused images to a magnetic field to thereby magnetize said magnetizable powder material thereon;

bringing the back surface of a second support sheet into contact with the surface of said first support sheet containing said fused magnetized images;

presenting a magnetically attractable powder to the front surface of said second support sheet to thereby develop reproductions of the xerographic images by the magnetic powder being attracted to said magnetized images; and

taining said magnetized images; presenting a magnetically attractable powder to the front surface of said second support sheet to thereby produce a second powder image of the original copy; transferring said second powder image to a final support surface;

transferring said second powder image to a final support from said intermediate surface; and fusing said powder image to said final support to produce permanent reproductions of the original copy.

3 53 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 526, 191 D t d September 1, 1970 lnv nt fl Morton Silverberq et al It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

r- Claim 7, column 6, lines 5 and 6, the phrase I "to a final support surface; should read--to an intermediate surface,-.

SIGNED Mu men mes-m (SEAL) Amt:

EdwardM-Fl It.

Y mm sum 1. Anemng Oflioer m at man 

